This invention relates to packagings used for the conditioning of various products, particularly food products, these packagings consisting in a tray made of thermoplastic material, this tray being tightly sealed with a welded-on sealing film after having been filled.
Packagings of this kind have the advantage of affording an excellent preservation of the packaged goods. Also, these packagings are easy to use, since it will be sufficient to remove the sealing film for releasing the contents.
However, these packagings have this drawback that they are designed for being laid flat, so that advertising mentions placed on the sealing film are not visible to potential buyers when such packagings are placed on display shelves or the like.
For eliminating this drawback, it has been suggested to provide the trays with a particular shape allowing them to remain stable in an upright position. For this purpose, two of the opposed walls of these trays are inclined in respect of a plane being perpendicular to the plane of the welded-on sealing film, instead of laying parallel to such a plane. This will then allow these trays to be placed in an upright position in which they can rest on a horizontal support, on the first part, along one side of their salient peripheral top rim, and, on the other part, along the lower side of the inclined wall which projects outwardly.
However, the manufacturing of such trays requires the use of special moulds which are relatively costly, for allowing the release of the male part of the mould being used. Moreover, the particular shape of these trays gives rise to further difficulties in the conditioning plants designed for producing such trays as well as for sealing them with a welded-on sealing film.
Therefore, it is an object of the present invention to provide a manufacturing device operating by moulding or thermoforming which is specially intended for the production of trays having slanted walls, this device being designed so as to avoid the drawbacks of earlier devices now being used for this production.